Plasticized gelatin and related proteinaceous colloids



United States 3,042,524 PLASTICIZED GELATIN AND RELATED PROTEINACEOUS COLLOiDS Charles P. lbus, Easton, Pa., and Donald E. Sargent, Burnt Hills, N .Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Feb. 12, 1958, Ser. No. 714,699

2 Claims. (Cl. 96-94) This invention relates to gelatin and similar proteinaceous colloids whose physical properties have been improved by incorporating therein certain plasticizing agents.

It is known to alter or modify the physical properties of Water-soluble prote'maceous colloids, i.e., gelatin, glue, casein, etc., by the addition thereto of various plasticizers such as glycerin, ethylene glycol, polyethylene glycol, and the like. These modifications become necessary in applications or processes that require the use of a colloid of the type described above, wherein some particular property of the colloid requires diminishing or enhancing.

Thus, gelatin which is a typical example of a watersoluble proteinaceous colloid has found extensive use as a carrier in various coating operations. Gelatin is of paremulsions and coatings produced therefrom. The one serious drawback, however, in using gelatin for the manufacture of photographic coatings concerns the high rate of planar contraction of the gelatin relative to the base.

. When such coatings are subjected to the drying operation, the photographic film emerges from the final drying step with a strong tendency to curl towards the coated or emulsion side. This curling characteristic of a photographic film makes for difficulty in handling and processing particularly in regard to roll film as the curling causes uneven winding during spooling operations.

Another difficulty frequently encountered with photographic film is its tendency to split or crack during storage under conditions of low humidity. This condition can be attributed to a prestressed state of the gelatin as a result of having been dried in contact with a base material whose rate of contraction on drying is much lower than that of the gelatin itself. Numerous remedies have been proposed to eliminate the problem of brittleness and curling of gelatin coatings. One of the commonly employed procedures is to add a plasticizer such as glycerin to the gelatin or other water-soluble colloid coating. Whereas such treatment has had limited success in reducing curl and brittleness of photographic film, the use of the afore said plasticizer has introduced other complications, i.e., the gelatin layer often becomes tacky and deteriorates because of high humidity and temperature conditions or the glycerin will sweat or bleed out of the dry gelatin coating. Another undesirable effect arising from the incorporation of glycerin in the gelatin layer of a photographic "ice We have now found that various polyhydric alcohols containing at least 4 carbon atoms, and polyhydric alcohols containing at least 4 carbon atoms and containing an ether group at least in the '7 carbon atom th reof are excellent plasticizers for proteinaceous water-soluble colloids such as gelatin, glue, casein, and the like.

Polyhydric alcohols which we have found particularly suitable as plasticizers are:

HOCH CH CHOHCH 1,3-butanediol CH CHOHCHOHCH 2,3-butanediol HOH C(CH CH OH Cljl-butanediol HOH C(CH CH OH 1,6-hexanediol HOH CCH CHOHCH OH 1,2,4-butanetrlol The aliphatic ethers of polyhydric alcohols contemplated herein are represented by the following general formula:

H CHr-|0H -CH7CHg0H wherein n is 1 to 6 and R is alkyl which may range from CH to C H R being ditferent in recurring units, if desired.

As examples. of ethers falling within the scope of the above formula, the following are representative:

HOHrCHrGHrOHgOI-I 3-methoxy-l butanol L OCHQJ:

3,5-dimethoxy-1-hexanol L 0 CH 8,5,7,9-tetramethoxy-1-decanol H CHr-(fHz CHrC HzOH 3,5,7 ,9,l1,13-hexamethoxy-1-tetradecanol Aliphatic ethers of polyhydric alcohols of the type used herein are obtained by the reaction of alkylvinyl ethers with various alcohols or from the reaction of acetals with alkylvinyl ethers followed by hydrolysis and hydrogenation. These reactions yield a mixture of alkoxy alcohols which can be separated by fractional distillation. Thus, the above methoxy alcohols can be prepared by reacting 3 moles of methyl vinyl ether with 1 mole of methanol followed by hydrolysis and hydrogenation.

Polyhydric alcohols of the type used herein are known compounds which have been described in the chemical literature and are commercially available.

In applying our invention, the gelatin solutions are prepared by dissolving dried gelatin in aqueous solutions of the polyhydric or polyalkoxy alcohols and the resulting gelatin solutions are coated on a suitable support. When such coatings are cast on glass and dried, the resulting films were found to be clear, compatible and equal to or superior to similar films plasticized with glycerin in flexibility.

A particularly useful embodiment of the present invention is the prevention of curling in coated photographic materials. The polyhydric or alkoxy alcohol plasticizers may be incorporated directly into the photographic emulsion prior to coating or the coated photographic materials can be rinsed with an aqueous solution of the aforesaid polyhydric or alkoxy alcohols following the final step of normal processing of such photographic materials. These coated photographic materials when so treated displayed much higher resistance to curling and brittleness when compared to control coatings given a like treatment with glycerin. In addition to the above advantages, the films rinsed with the aqueous polyhydric or alkoxy alcohol solutions showed very low susceptibility toward mold growth-.-

The above described treatment possesses the added ad vantage of improving the handling properties of photographic film thus facilitating splicing or projector threading. Such film is much more limp than the untreated film and has a pleasing waxy feeling to the hand.

In all instances where the plasticizers are added to the proteinaceous water-soluble colloids after said colloids have been coated, we have found that generally satisfactory results ensue by treating such coatings with a bath containing 1 to (by volume) of the polyhydric or alkoxy alcohol plasticizer. Particularly good results are obtained with a 5% (by volume) solution of the plasticizing alcohol in a three minute rinse application. If the plasticizers are added directly to the proteinaceous colloid, the amount used should be about 1.0% by weight of the colloid.

It is to be understood that our invention is not limited or narrowed to any particular variety of photographic material and is equally applicable to color film as well as black and white film.

The following examples will serve to illustrate this invention in greater detail without, however, imposing any restriction thereon.

Example I A section of freshly processed 35 mm. color film was threaded through a tank containing an aqueous solution of 5% (by volume) of 1,2,4-butanetriol. After a three minute treatment, the film was air-squeegeed and run through a dryer. The film emerged from the drying cabinet in a very flat condition and was readily spooled. Another freshly processed section which had not been similarly treated showed a very pronounced curl toward the emulsion side and required constant surveillance during the spooling operation to avoid uneven winding.

Samples of the film not treated with butanetriol (type) and samples so treated were suspended in low humidity (14%) and high humidity (84%) cells. The type curled significantly at low humidity while the butanetriol treated sample showed only a slight curl. Inspection of the high humidity samples revealed no sweating out" or tackiness on the butanetriol sample.

Additional samples were placed in a high humidity oven to investigate ageing conditions. After 60 hours exposure, inspection of each sample revealed no difference between the treated and type in regard to stain or dye decolorization. The butanetriol sample still had improved curl properties.

Example 11 Freshly processed 35 mm. color film Was treated with a 2% (by volume) aqueous solution of 1,4-butanediol. The procedure and results obtained therefrom were very similar to Example I.

4 Example III Freshly processed 35 mm. 0010; film= was treated with a 5% (by volume) aqueous solution of 1,2,6-hexanetrio1. The procedure and results obtained therefrom were very similar to Example 1.

Example IV The gelatin composition in this example was prepared as given in Example IV with the exception that in this instance 1,2,4-butanetriol was used as the plasticzer in place of 1,4-butanediol. Similar results were obtained in this case.

Example VI The following compositions were prepared:

Composition 1 2 3 4 Non-curling gelatin (parts by weight) 10 10 10 10 1% 3-Methoxy-1-butanol solution (parts by weight) 10 1% 3,5-Dimethoxy-1-hexanol solution (parts by weight) 10 1% 3,5,7,9-Tetramethoxy-1 decanol solution (parts by weight) 10 Water 80 8O 80 2 centimeters of an 8% solution were added to each of the above gelatin compositions containing the aforementioned alkoxy alcohols as plasticizers; 4 served as the control.

When cast on glass and dried, these plasticized gelatin compositions yielded clear and compatible films.

In each case, the plasticized compositions 1, 2, and 3 were found to be much more flexible than the brittle control composition 4.

We claim:

1. A photographic element comprising a support and a gelatin layer containing a light-sensitive silver halide salt wherein said gelatin layer is plasticized with a plasticizing amount of 1,2,4-butanetriol.

2. A photographic element as defined in claim. 1 wherein said plasticizing amount is about 1% by weight based on the weight of gelatin in the layer.

References Cited in the file of this patent UNITED STATES PATENTS 797,458 Rompler Aug. 15, 1905 1,757,482 Seel May 6, 1930 2,129,242 Sheppard et a1. Sept. 6, 1938 2,190,645 Boomer Feb. 20, 1940 2,240,469 Swan et al. Apr. 29, 1941 2,423,549 Blake et a1. July 8, 1947 2,476,976 Grunfeld July 26, 1949 2,618,663 Glickman Nov. 18, 1952 2,629,659 Mueller Feb. 24, 1953 2,960,404 Milton et al. Nov. 15, 1960 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT AND A GELATIN LAYER CONTAINING A LIGHT-SENSITIVE SILVER HALIDE SALT WHEREIN SAID GELATIN LAYER IS PLASTICIZED WITH A PLASTICIZING AMOUNT OF 1,2,4-BUTANETRIOL. 